1. Field of the Invention
The present invention relates to technology for detecting whether precision equipment is subjected to an impact while it was being transported.
2. Description of the Related Art
When goods such as precision equipment are shipped, the goods may be damaged depending on the handling conditions. If a magnitude of impact on the goods does not exceed a damage boundary, by taking damage-preventive measures based on a prior damage evaluation by a packaging condition, it is possible to prevent the goods from being damaged.
For example, Japanese Patent Application Laid-open No. 2001-108703 discloses an impact detection display member that can be attached to a packaging good. The impact detection display member includes a weight having a smooth surface capable of reflecting an incident light and a beam supporting the weight. When the packaging good to which the impact detection display member is attached is subjected to an impact, for example, by being dropped, the impact detection display member detects the impact because the weight is inclined. Therefore, people can visually confirm whether the packaging good was subjected to an impact based on whether the weight is inclined. However, this technology is disadvantageous in that the impact detection display member has a complicated structure and has difficulty detecting an impact in both a longitudinal direction and a lateral direction. The same goes for a technology disclosed in Japanese Patent Application Laid-open No. 2001-199475.
NIPPON KAKO-KIZAI CO., LTD. has manufactured and marketed an impact detector “DROP SIGN”. The impact detector is, as shown in FIGS. 19A and 19B, composed of a front case 11, a rear case 12, a leaf spring 13, a leaf-spring fixation portion 14, a guide plate 15, a colored weight 16, and upper and lower window holes 17. The impact detector is attached to an object subject to impact detection in a state where a long side of which is oriented in a longitudinal direction so as to detect a longitudinal impact. Specifically, while the object is not subjected to any impact, the weight 16 is held in the middle of the case by the leaf spring 13. When the object is subjected to a longitudinal impact, the weight 16 moves either upward or downward across the leaf spring 13. For example, when the weight 16 moves downward, the color of the weight 16 can be seen through the lower window hole 17. Therefore, people can visually confirm the downward movement of the weight 16, i.e., can recognize that the object is subjected to the impact. However, in this configuration, when the object is dropped and subjected to a longitudinal impact, the weight 16 moves downward across the leaf spring 13 with bending the leaf spring 13 downward by force. In other words, the weight 16 is configured to move in one axial direction only. Therefore, the impact detector can detect the longitudinal impact but cannot detect whether the object is overturned (fallen) on its side. Alternatively, if the impact detector is attached to the object in a state where the long side of which is oriented in a lateral direction, the impact detector can detect a lateral impact, i.e., whether the object is overturned (fallen) on its side, but cannot detect a longitudinal impact. This means the impact detector can detect either a longitudinal impact or a lateral impact only. Therefore, to detect both a longitudinal impact and a lateral impact, it is necessary to attach two impact detectors to the object in different orientations.
Moreover, in an impact detector as disclosed in Japanese Patent Application Laid-open No. 2003-207515, Japanese Patent Application Laid-open No. 2006-53073, Utility Model Application Laid-open No. H04-43266, and Utility Model Application Laid-open No. H04-34614, a spherical weight is supported on a relatively large face of an elastic member. When an object to which the impact detector is attached is subjected to an impact, the weight moves to be exposed, which means that the object is subjected to the impact.
However, even with the above conventional technologies, it is still difficult to prevent goods from being damaged completely if the goods are subjected to a greater-than-expected magnitude of impact, for example, by being dropped or fallen accidentally or handled roughly by a carrier.
When a packaging of goods is significantly damaged by an impact, it is possible to find the damage on the goods at the time of inspection of the goods before the goods are delivered to a customer or a shop. However, there is a possibility that only the goods are damaged even though the packaging is not apparently damaged. In this case, the damage on the goods is found after the goods are delivered to the customer or the shop, which results in a complaint and erosion of customer's trust.